Firstly, yes. You can make a lot of things in Python. IDLE's GUI was written in Python, if I remember correctly. I think that Red Hat used to use Python for some GUI parts.
You can also make games using PyGame, www.pygame.org.
You can use Java's Swing GUI in Jython, if you like, www.jython.org.
And so on and so on...
As for the IDE, I use eric, and am content with it.

Hi,
I think you can start with DrPython -- an open-source simple IDE for Python.
Not only providing regular text editor functions, it also comes with an embeded Python interpreter, so it's very convinence to quickly do some "experiments" while you are do some serious programming.
It also support plug-ins, and with "CodeCompletion" (use the latest version 0.0.3), newbies could get many hints while coding.
Another reason why I recommend DrPython to you it that, I have noticed DrPython had been one of the most active project in SourceForge.Net. It even reached 100% active percentage last month! So we have every reasons to believe that it will become better.
As of GUI programming in Python, I can tell you that DrPython is just written in wxPython, a very powerful cross platform GUI liberary for python.

I can find my fiar share of tutorials, but they do nothing but say "This is a hello world program" then show me the code. I can't find anything that will tell me "You will always need to put a tab here" or "After this, you will always need a space". Its one thing to mimic the syntax, but I am looking to understand it.